1. Field of the Invention:
The present invention relates to a torque transmitting device, and more particularly to a torque transmitting device of the viscous coupling type having a differential function through the utilization of fluid viscosity.
2. Description of Prior Art:
Recently, torque transmitting devices in the form of a viscous coupling for transmitting a torque through the viscosity of a fluid have been widely employed as automotive differentials.
For example, Japanese Laid-Open Patent Publication No. 58-50349 discloses a torque transmitting device comprising a cylindrical housing having a fluid chamber defined therein and filled with a fluid, a pair of coaxial shafts having confronting ends rotatably supported in the housing, a plurality of annular outer plates disposed in the fluid chamber for rotation with the housing, and a plurality of annular inner plates disposed in the housing alternately with the outer plates for rotation with the shafts.
The housing and the outer plates are coupled to each other by their respective inner teeth and outer teeth which are held in mesh with each other, and the shafts and the inner plates are also coupled to each other by their respective outer teeth and inner teeth which are held in mesh with each other. The torque transmitting device of this type is widely used to connect two coaxial shafts or as a differential between the rear road wheels of an automobile.
When the housing is rotated, the shafts are rotated at the same time by the viscosity of the fluid present between the outer plates and the inner plates.
If the shafts can be rotated with a certain positive time lag therebetween, then various advantages will be produced. Particularly, where the torque transmitting device is used as a differential between the rear road wheels of an automobile, if the shafts can be rotated with a certain time lag therebetween, a restoring moment produced on the automobile by a driving force acting on the inner road wheel and a braking force acting on the outer road wheel can be reduced, thus allowing the automobile to make turns with greater ease.